#include <cstdio>

int main( )
{
    bool f[ 16001 ];
    int i, j, t;
    for ( i = 1; i <= 16000; i++ )
        f[ i ] = true;
    f[ 1 ] = false;
    for ( i = 2; i <= 16000; i++ )
        if ( f[ i ] )
            for ( j = i * 2; j <= 16000; j += i )
                f[ j ] = false;
    i = 0;
    f[ 2 ] = false;
    while ( scanf("%d", &t ) )
    {
        if ( t <= 0 )
            break;
        i++;
        printf("%d: ", i);
        if ( f[ t ] )
            printf("yes\n");
        else
            printf("no\n");
    }
    return 0;
}
